The present invention relates to document handling equipment and, more particularly, to devices for stacking documents exiting from such document handling equipment.
Mechanical devices for moving documents at high speed as part of a system that reads or operates on the documents are well known. Such systems include photocopiers, optical character readers and sorters. A typical system of this type will accept a stack of documents at its input. These documents are fed into the system automatically, processed, and then ejected into one or more output stacks.
U.S. Pat. No. 4,171,129 to Daley et al., which is assigned to the assignee of the present invention, discloses a document transport for an optical character recognition system (OCR). In this system a stack of documents is is loaded onto an elevator which lifts the document stack until the topmost document contacts a feed roller which pushes it between a set of separator rollers that make sure that only one document at a time is taken into the system. An alignment gate operating in conjunction with pinch rollers causes alignment of the document with the paper path. Next the document is moved at a controlled speed past an optically-sensitive device so that the characters printed thereon may be read by the system. Once the document has passed the reading station it is moved at high speed to either an accept or reject bin where it is stacked along with other documents.
The documents processed in the Daley et al. patent enter the accept or reject bins at high speed and hit the rear wall of the bin. They rebound from this collision and float down onto the stack of earlier documents in the bottom of the bin. When the documents are moving at high speed, it is possible for a following document to run into a rebounding document, whereby the orderly stacking of the documents is interrupted.